To comply with NIST requirements for data protection, PhantomPDF on Windows can provide encryption via the Federal Information Processing Standard (FIPS) 140-2 mode.
FIPS 140 is a cryptographic security standard used by the United States federal government and others requiring higher degrees of security. Foxit utilizes certified and unmodified encryption modules licensed from Microsoft CryptoAPI built with Cryptographic Primitives Library (Which is 140-2 certified)
Therefore, Foxit will not show up in the NIST Cryptographic Module Validation Program vendor lists. When the FIPS mode is enabled via the registry, encryption in digital signature workflows use FIPS-approved algorithms during the production of PDFs (not the consumption of PDFs).